This invention relates generally to insulation-piercing electrical contacts and connectors incorporating such contacts and, more particularly, to insulation-piercing electrical contacts for use in modular plug connectors and to modular plug connectors incorporating such insulation-piercing electrical contacts.
Modular plug connectors are widely used in the telephone and data communication fields to terminate flat multi-conductor cables including a plurality of insulated conductors arranged in a spaced linear array within an outer jacket. Examples of such connectors are disclosed in U.S. Pat. Nos. 3,860,316 to Hardesty and 4,211,462 to Wolfthal.
After removing the end portion of the cable outer jacket, the exposed insulated conductors are inserted into adjacent channels formed in the connector housing, whereupon a plurality of flat contacts corresponding in number to the number of conductors in the cable are inserted into respective slots formed in the connector housing aligned with respective channels in which the insulated conductors are situated. Each contact has a pair of blades which pierce the insulation of a corresponding conductor and the conductor itself, which is conventionally formed of soft tinsel material, to thereby provide a solderless electrical connection. Each contact has a flat top edge surface adapted to electrically engage a respective jack contact when the plug connector is inserted into a jack receptacle.
It would be desirable to use solid or stranded conductors in the multi-conductor cables in lieu of the soft tinsel conductors since tinsel material is relatively expensive and easily broken. However, since solid or stranded conductors are relatively hard, it is generally not possible to use the conductor-piercing contact described above with such conductor material. It would therefore be desirable to provide a contact which could be used with solid or stranded conductors.
Several contact constructions for terminating solid or stranded conductors have been suggested. For example, reference is made to U.S. Pat. Nos. 3,816,818 to Meier, 4,089,580 to Huffnagle, 4,270,831 to Takahashi and 4,431,246 to Vaden.
The Meier '818 patent discloses a contact for use in a non-modular type connector, including two end insulation-piercing tines and an intermediate insulation-piercing tine which are longitudinally spaced from each other in transversely offset pattern with respect to the longitudinal axis of the cable conductors. The contact is formed so that upon termination the inner surfaces of the end tines will lie adjacent to and electrically engage one side of the solid conductor while the inner surface of the intermediate tine will lie adjacent to and electrically engage the other side of the solid conductor.
The Huffnagle '580 patent discloses a contact for use in a non-modular type connector for terminating a non-insulated solid conductor. The contact includes two end arms and an intermediate arm which are longitudinally spaced from each other in a transversely offset pattern. Each of the arms has a concave configuration so that when a conductor is pressed into the spaces between the contact arms, it engages the opposed corner edges of the arms between adjacent arms.
The Takahashi '831 patent discloses a contact for use in a non-modular type connector which includes a first angular tine, a second angular tine oppositely disposed at the same angle as that of the first tine, and a third tine disposed at a different angle from that of the first and second tines so that the center thereof is on the lateral centerline of the space between the tines. The tines define press-in openings between their corner edges for connection to a solid conductor.
The Vaden '246 patent discloses a contact for use in a modular type connector including first and second adjacent insulation-piercing tines which are situated next to each other without any longitudinal space between them. The tines are adapted to bend or flare laterally outwardly in opposite directions when the conductor is terminated to provide a sort of crimped electrical connection.
It is important to obtain an electrical connection between the contact and conductor which is as reliable as possible. The construction of modular plug connectors presents certain limitations which should be taken into account in the design of the contact so that conventional contacts designed for use in non-modular connectors are not always suitable. Moreover, conventional contacts designed for modular plug connectors are not entirely satisfactory. For example, in the case of the contact described in the Vaden '246 patent, it is not uncommon for a tine which engages one conductor to pierce the partition wall separating adjacent conductor-receiving channels of the modular plug connector and pass into the adjacent channel as it bends outwardly and thereby engage an adjacent conductor. This of course, results in a defective connector.